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Saadeh K, Fazmin IT. Mitochondrial Dysfunction Increases Arrhythmic Triggers and Substrates; Potential Anti-arrhythmic Pharmacological Targets. Front Cardiovasc Med 2021; 8:646932. [PMID: 33659284 PMCID: PMC7917191 DOI: 10.3389/fcvm.2021.646932] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 01/26/2021] [Indexed: 12/31/2022] Open
Abstract
Incidence of cardiac arrhythmias increases significantly with age. In order to effectively stratify arrhythmic risk in the aging population it is crucial to elucidate the relevant underlying molecular mechanisms. The changes underlying age-related electrophysiological disruption appear to be closely associated with mitochondrial dysfunction. Thus, the present review examines the mechanisms by which age-related mitochondrial dysfunction promotes arrhythmic triggers and substrate. Namely, via alterations in plasmalemmal ionic currents (both sodium and potassium), gap junctions, cellular Ca2+ homeostasis, and cardiac fibrosis. Stratification of patients' mitochondrial function status permits application of appropriate anti-arrhythmic therapies. Here, we discuss novel potential anti-arrhythmic pharmacological interventions that specifically target upstream mitochondrial function and hence ameliorates the need for therapies targeting downstream changes which have constituted traditional antiarrhythmic therapy.
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Affiliation(s)
- Khalil Saadeh
- School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom.,Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Ibrahim Talal Fazmin
- School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom.,Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,Royal Papworth Hospital NHS Foundation Trust, Cambridge, United Kingdom
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2
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Sharma N, Cortez D, Disori K, Imundo JR, Beck M. A Review of Long QT Syndrome: Everything a Hospitalist Should Know. Hosp Pediatr 2020; 10:369-375. [PMID: 32144177 DOI: 10.1542/hpeds.2019-0139] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In this article, we will review various aspects of long QT syndrome (LQTS) necessary for hospitalists who care for children, adolescents, and young adults who have known LQTS and also review presenting features that should make one consider LQTS as a cause of hospitalization. Pediatric hospitalists care for patients who have suffered near-drowning, unexplained motor vehicular accidents, brief resolved unexpected events, sudden infant death syndrome, recurrent miscarriages, syncope, or seizures. These common conditions can be clinical clues in patients harboring 1 of 16 LQTS genetic mutations. LQTS is commonly caused by a channelopathy that can cause sudden cardiac death. Over the years, guidelines on management and recommendations for sports participation have evolved with our understanding of the disease and the burden of arrhythmias manifested in the pediatric age group. This review will include the genetic causes of LQTS, clinical features, and important historical information to obtain when these presentations are encountered. We will review medical and surgical treatments available to patients with LQTS and long-term care recommendations and prognosis for those diagnosed with LQTS.
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Affiliation(s)
| | - Daniel Cortez
- Division of Adult Electrophysiology, Department of Cardiology, Penn State Medical Center, Hershey, Pennsylvania; and.,Department of Cardiology, University of Lund, Lund, Sweden
| | - Kristin Disori
- Pediatric Hospital Medicine, Department of Pediatrics, Penn State Children's Hospital, Hershey, Pennsylvania
| | | | - Michael Beck
- Pediatric Hospital Medicine, Department of Pediatrics, Penn State Children's Hospital, Hershey, Pennsylvania;
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3
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Skinner JR, Winbo A, Abrams D, Vohra J, Wilde AA. Channelopathies That Lead to Sudden Cardiac Death: Clinical and Genetic Aspects. Heart Lung Circ 2019; 28:22-30. [DOI: 10.1016/j.hlc.2018.09.007] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 09/20/2018] [Accepted: 09/23/2018] [Indexed: 12/19/2022]
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Pérez-Riera AR, Barbosa-Barros R, Daminello Raimundo R, da Costa de Rezende Barbosa MP, Esposito Sorpreso IC, de Abreu LC. The congenital long QT syndrome Type 3: An update. Indian Pacing Electrophysiol J 2018; 18:25-35. [PMID: 29101013 PMCID: PMC5840852 DOI: 10.1016/j.ipej.2017.10.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 10/27/2017] [Accepted: 10/30/2017] [Indexed: 01/28/2023] Open
Abstract
Congenital long QT syndrome type 3 (LQT3) is the third in frequency compared to the 15 forms known currently of congenital long QT syndrome (LQTS). Cardiac events are less frequent in LQT3 when compared with LQT1 and LQT2, but more likely to be lethal; the likelihood of dying during a cardiac event is 20% in families with an LQT3 mutation and 4% with either an LQT1 or an LQT2 mutation. LQT3 is consequence of mutation of gene SCN5A which codes for the Nav1.5 Na+ channel α-subunit and electrocardiographically characterized by a tendency to bradycardia related to age, prolonged QT/QTc interval (mean QTc value 478 ± 52 ms), accentuated QT dispersion consequence of prolonged ST segment, late onset of T wave and frequent prominent U wave because of longer repolarization of the M cell across left ventricular wall.
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Affiliation(s)
- Andrés Ricardo Pérez-Riera
- Metodologia da Pesquisa e Escrita Científica da Faculdade de Medicina do ABC, Santo André, São Paulo, Brazil.
| | - Raimundo Barbosa-Barros
- Centro Coronariano do Hospital de Messejana Dr. Carlos Alberto Studart Gomes, Fortaleza, Ceará, Brazil
| | - Rodrigo Daminello Raimundo
- Metodologia da Pesquisa e Escrita Científica da Faculdade de Medicina do ABC, Santo André, São Paulo, Brazil
| | | | | | - Luiz Carlos de Abreu
- Program in Molecular and Integrative Physiological Sciences (MIPS), Department of Environmental Health, Harvard T.H. Chan School of Public Health, USA
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Maltese PE, Orlova N, Krasikova E, Emelyanchik E, Cheremisina A, Kuscaeva A, Salmina A, Miotto R, Bonizzato A, Guerri G, Zuntini M, Nicoulina S, Bertelli M. Gene-Targeted Analysis of Clinically Diagnosed Long QT Russian Families. Int Heart J 2016; 58:81-87. [PMID: 28003625 DOI: 10.1536/ihj.16-133] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Long QT syndrome (LQTS) has great genetic heterogeneity: more than 500 mutations have been described in several genes. Despite many advances, a genetic diagnosis still cannot be established in 25-30% of patients. The aim of the present study was to perform genetic evaluation in 9 Russian families with LQTS; here we report the results of 4 positive probands and their relatives (a total of 16 individuals). All subjects underwent clinical examination, 12-lead ECG, and Holter monitoring. Genetic analysis of the 14 genes mainly involved in LQTS was performed using a next-generation sequencing approach. We identified two new mutations (KCNQ1 gene) and 6 known mutations (AKAP9, ANK2, KCNE1 and KCNJ2 genes) in 4 out of 9 probands, some of which have already been described in association with LQTS. Segregation studies suggest a possible causative role for KCNQ1 p.(Leu342Pro), AKAP9 p.(Arg1609Lys), KCNE1 p.(Asp85Asn), and KCNJ2 p.(Arg82Gln) variations. Our study confirmed the high genetic heterogeneity of this disease and highlights the difficulties to reveal clear pathogenic genotypes also in large pedigrees. To the best of our knowledge, this is the first genetic study of LQTS patients from Russian families.
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Geavlete DO, Ionita O, Mandes L, Kulcsar I, Stoica E, Ciudin R, Macarie C, Chioncel O. Resuscitation of sudden cardiac death caused by acute epileptic seizures: A case report. JOURNAL OF ACUTE DISEASE 2016. [DOI: 10.1016/j.joad.2015.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Abstract
Long QT syndrome (LQTS) is a potentially life-threatening cardiac arrhythmia characterized by delayed myocardial repolarization that produces QT prolongation and increased risk for torsades des pointes (TdP)-triggered syncope, seizures, and sudden cardiac death (SCD) in an otherwise healthy young individual with a structurally normal heart. Currently, there are three major LQTS genes (KCNQ1, KCNH2, and SCN5A) that account for approximately 75% of the disorder. For the major LQTS genotypes, genotype-phenotype correlations have yielded gene-specific arrhythmogenic triggers, electrocardiogram (ECG) patterns, response to therapies, and intragenic and increasingly mutation-specific risk stratification. The 10 minor LQTS-susceptibility genes collectively account for less than 5% of LQTS cases. In addition, three atypical LQTS or multisystem syndromic disorders that have been associated with QT prolongation have been described, including ankyrin-B syndrome, Anderson-Tawil syndrome (ATS), and Timothy syndrome (TS). Genetic testing for LQTS is recommended in patients with either a strong clinical index of suspicion or persistent QT prolongation despite their asymptomatic state. However, genetic test results must be interpreted carefully.
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Aromolaran AS, Subramanyam P, Chang DD, Kobertz WR, Colecraft HM. LQT1 mutations in KCNQ1 C-terminus assembly domain suppress IKs using different mechanisms. Cardiovasc Res 2014; 104:501-11. [PMID: 25344363 DOI: 10.1093/cvr/cvu231] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
AIMS Long QT syndrome 1 (LQT1) mutations in KCNQ1 that decrease cardiac IKs (slowly activating delayed rectifier K(+) current) underlie ventricular arrhythmias and sudden death. LQT1 mutations may suppress IKs by preventing KCNQ1 assembly, disrupting surface trafficking, or inhibiting gating. We investigated mechanisms underlying how three LQT1 mutations in KCNQ1 C-terminus assembly domain (R555H/G589D/L619M) decrease IKs in heterologous cells and cardiomyocytes. METHODS AND RESULTS In Chinese hamster ovary (CHO) cells, mutant KCNQ1 + KCNE1 channels either produced no currents (G589D/L619M) or displayed markedly reduced IKs with a right-shifted voltage-dependence of activation (R555H). When co-expressed with wild-type (wt) KCNQ1, the mutant KCNQ1s displayed varying intrinsic dominant-negative capacities that were affected by auxiliary KCNE1. All three mutant KCNQ1s assembled with wt KCNQ1 as determined by fluorescence resonance energy transfer (FRET). We developed an optical quantum dot labelling assay to measure channel surface density. G589D/R555H displayed substantial reductions in surface density, which were either partially (G589D) or fully (R555H) rescued by wt KCNQ1. Unexpectedly, L619M showed no trafficking defect. In adult rat cardiomyocytes, adenovirus-expressed homotetrameric G589D/L619M + KCNE1 channels yielded no currents, whereas R555H + KCNE1 produced diminished IKs with a right-shifted voltage-dependence of activation, mimicking observations in CHO cells. In contrast to heterologous cells, homotetrameric R555H channels showed no trafficking defect in cardiomyocytes. CONCLUSION Distinct LQT1 mutations in KCNQ1 assembly domain decrease IKs using unique combinations of biophysical and trafficking mechanisms. Functional deficits in IKs observed in heterologous cells are mostly, but not completely, recapitulated in adult rat cardiomyocytes. A 'methodological chain' combining approaches in heterologous cells and cardiomyocytes provides mechanistic insights that may help advance personalized therapy for LQT1 mutations.
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Affiliation(s)
- Ademuyiwa S Aromolaran
- Department of Physiology and Cellular Biophysics, Columbia University, College of Physicians and Surgeons, 1150 St. Nicholas Avenue, 504 Russ Berrie, New York, NY 10032, USA
| | - Prakash Subramanyam
- Department of Physiology and Cellular Biophysics, Columbia University, College of Physicians and Surgeons, 1150 St. Nicholas Avenue, 504 Russ Berrie, New York, NY 10032, USA
| | - Donald D Chang
- Department of Physiology and Cellular Biophysics, Columbia University, College of Physicians and Surgeons, 1150 St. Nicholas Avenue, 504 Russ Berrie, New York, NY 10032, USA
| | - William R Kobertz
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School Worcester, MA 01605, USA
| | - Henry M Colecraft
- Department of Physiology and Cellular Biophysics, Columbia University, College of Physicians and Surgeons, 1150 St. Nicholas Avenue, 504 Russ Berrie, New York, NY 10032, USA
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Dohadwala M, Link MS. Implantable Defibrillators in Long QT Syndrome, Brugada Syndrome, Hypertrophic Cardiomyopathy, and Arrhythmogenic Right Ventricular Cardiomyopathy. Cardiol Clin 2014; 32:305-18. [DOI: 10.1016/j.ccl.2013.11.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Takahashi K, Shimizu W, Miyake A, Nabeshima T, Nakayashiro M, Ganaha H. High Prevalence of the SCN5A E1784K Mutation in School Children With Long QT Syndrome Living on the Okinawa Islands. Circ J 2014; 78:1974-9. [DOI: 10.1253/circj.cj-13-1516] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Wataru Shimizu
- Department of Cardiovascular Medicine, Nippon Medical School
| | - Akira Miyake
- Department of Pediatric Cardiology, Okinawa Children’s Medical Center
| | - Taisuke Nabeshima
- Department of Pediatric Cardiology, Okinawa Children’s Medical Center
| | - Mami Nakayashiro
- Department of Pediatric Cardiology, Okinawa Children’s Medical Center
| | - Hitoshi Ganaha
- Department of Pediatric Cardiology, Okinawa Children’s Medical Center
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Mahida S, Hogarth AJ, Cowan C, Tayebjee MH, Graham LN, Pepper CB. Genetics of congenital and drug-induced long QT syndromes: current evidence and future research perspectives. J Interv Card Electrophysiol 2013; 37:9-19. [PMID: 23515882 DOI: 10.1007/s10840-013-9779-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 01/07/2013] [Indexed: 12/17/2022]
Abstract
The long QT syndrome (LQTS) is a condition characterized by abnormal prolongation of the QT interval with an associated risk of ventricular arrhythmias and sudden cardiac death. Congenital forms of LQTS arise due to rare and highly penetrant mutations that segregate in a Mendelian fashion. Over the years, multiple mutations in genes encoding ion channels and ion channel binding proteins have been reported to underlie congenital LQTS. Drugs are by far the most common cause of acquired forms of LQTS. Emerging evidence suggests that drug-induced LQTS also has a significant heritable component. However, the genetic substrate underlying drug-induced LQTS is presently largely unknown. In recent years, advances in next-generation sequencing technology and molecular biology techniques have significantly enhanced our ability to identify genetic variants underlying both monogenic diseases and more complex traits. In this review, we discuss the genetic basis of congenital and drug-induced LQTS and focus on future avenues of research in the field. Ultimately, a detailed characterization of the genetic substrate underlying congenital and drug-induced LQTS will enhance risk stratification and potentially result in the development of tailored genotype-based therapies.
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Affiliation(s)
- Saagar Mahida
- Leeds General Infirmary, Great George Street, Leeds, LS1 3EX, UK.
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Abriel H, Zaklyazminskaya EV. A modern approach to classify missense mutations in cardiac channelopathy genes. ACTA ACUST UNITED AC 2013; 5:487-9. [PMID: 23074335 DOI: 10.1161/circgenetics.112.964809] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Aidery P, Kisselbach J, Schweizer PA, Becker R, Katus HA, Thomas D. Impaired ion channel function related to a common KCNQ1 mutation — Implications for risk stratification in long QT syndrome 1. Gene 2012; 511:26-33. [DOI: 10.1016/j.gene.2012.09.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 09/05/2012] [Accepted: 09/11/2012] [Indexed: 11/28/2022]
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Beckmann BM, Kääb S. [Genetic testing in hereditary arrythmia syndromes today and in the future]. Herzschrittmacherther Elektrophysiol 2012; 23:161-166. [PMID: 22993117 DOI: 10.1007/s00399-012-0230-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Accepted: 07/20/2012] [Indexed: 06/01/2023]
Abstract
Genetic testing already has a substantial impact in identifying hereditary arrhythmia syndromes after sudden death in young patients. This report provides information on current developments, available options and reasonable approaches in the clinical setting. In addition the limitations of genetic testing are discussed. Genetic testing is only useful for patients in the context of clinical findings interpreted by an experienced cardiogenetics team.
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Affiliation(s)
- Britt-Maria Beckmann
- Medizinische Klinik und Poliklinik I, Ludwig-Maximilians-Universität München, D-81377, München, Germany.
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Modell SM, Bradley DJ, Lehmann MH. Genetic testing for long QT syndrome and the category of cardiac ion channelopathies. PLOS CURRENTS 2012; 4:e4f9995f69e6c7. [PMID: 22872816 PMCID: PMC3392134 DOI: 10.1371/4f9995f69e6c7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Cardiac ion channel mutational analysis is a category of genetic testing used in clinical practice for determining the status of long QT syndrome, short QT syndrome, catecholaminergic polymorphic ventricular tachycardia, and Brugada syndrome genes in blood, saliva, or tissue from patients and family members at risk for cardiac events such as syncope and sudden death. Such testing is most informative following careful phenotypic characterization. Individuals with ion channelopathies may benefit from prevention (avoidance of triggers and predisposing drugs) and treatment (e.g., beta blocker therapy, implantable cardioverter-defibrillator (ICD) placement) modalities.
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Affiliation(s)
- Simon Modi
- Arrhythmia Service, London Health Sciences Centre, 339 Windermere Road, London, Ontario, Canada
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Sreeram N, Trieschmann U, Khalil M, Emmel M. Risk stratification in young patients with channelopathies. Indian Pacing Electrophysiol J 2010; 10:257-73. [PMID: 20552061 PMCID: PMC2880872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Identifying the young patient at risk of malignant arrhythmias and sudden cardiac death remains a challenge. It is increasingly recognised that sudden death, syncope and aborted cardiac arrest at a young age in patients with a structurally normal heart may be the result of various ion channel disorders - the channelopathies. The approach to risk stratification involves a combination of the clinical presentation, taken in conjunction with the family history, genetic testing, invasive electrophysiological studies or other provocative tests where appropriate and feasible. A logical approach to risk stratification in some of the commoner channelopathies seen in paediatric practice is presented.
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Affiliation(s)
- N Sreeram
- Department of Paediatric Cardiology. University Hospital of Cologne, Germany
| | - U Trieschmann
- Paediatric Cardiac Anaesthesia and Intensive Care Medicine, University Hospital of Cologne, Germany
| | - M Khalil
- Department of Paediatric Cardiology. University Hospital of Cologne, Germany
| | - M Emmel
- Department of Paediatric Cardiology. University Hospital of Cologne, Germany
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ZHAO JINGTING, HILL ADAMP, VARGHESE ANTHONY, COOPER ANTONYA, SWAN HEIKKI, LAITINEN-FORSBLOM PÄIVIJ, REES MARKI, SKINNER JONATHANR, CAMPBELL TERENCEJ, VANDENBERG JAMIEI. Not All hERG Pore Domain Mutations Have a Severe Phenotype: G584S Has an Inactivation Gating Defect with Mild Phenotype Compared to G572S, Which Has a Dominant Negative Trafficking Defect and a Severe Phenotype. J Cardiovasc Electrophysiol 2009; 20:923-30. [DOI: 10.1111/j.1540-8167.2009.01468.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Hothi SS, Thomas G, Killeen MJ, Grace AA, Huang CLH. Empirical correlation of triggered activity and spatial and temporal re-entrant substrates with arrhythmogenicity in a murine model for Jervell and Lange-Nielsen syndrome. Pflugers Arch 2009; 458:819-35. [PMID: 19430811 PMCID: PMC2719739 DOI: 10.1007/s00424-009-0671-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2009] [Accepted: 04/07/2009] [Indexed: 11/23/2022]
Abstract
KCNE1 encodes the β-subunit of the slow component of the delayed rectifier K+ current. The Jervell and Lange-Nielsen syndrome is characterized by sensorineural deafness, prolonged QT intervals, and ventricular arrhythmogenicity. Loss-of-function mutations in KCNE1 are implicated in the JLN2 subtype. We recorded left ventricular epicardial and endocardial monophasic action potentials (MAPs) in intact, Langendorff-perfused mouse hearts. KCNE1−/− but not wild-type (WT) hearts showed not only triggered activity and spontaneous ventricular tachycardia (VT), but also VT provoked by programmed electrical stimulation. The presence or absence of VT was related to the following set of criteria for re-entrant excitation for the first time in KCNE1−/− hearts: Quantification of APD90, the MAP duration at 90% repolarization, demonstrated alterations in (1) the difference, ∆APD90, between endocardial and epicardial APD90 and (2) critical intervals for local re-excitation, given by differences between APD90 and ventricular effective refractory period, reflecting spatial re-entrant substrate. Temporal re-entrant substrate was reflected in (3) increased APD90 alternans, through a range of pacing rates, and (4) steeper epicardial and endocardial APD90 restitution curves determined with a dynamic pacing protocol. (5) Nicorandil (20 µM) rescued spontaneous and provoked arrhythmogenic phenomena in KCNE1−/− hearts. WTs remained nonarrhythmogenic. Nicorandil correspondingly restored parameters representing re-entrant criteria in KCNE1−/− hearts toward values found in untreated WTs. It shifted such values in WT hearts in similar directions. Together, these findings directly implicate triggered electrical activity and spatial and temporal re-entrant mechanisms in the arrhythmogenesis observed in KCNE1−/− hearts.
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Affiliation(s)
- Sandeep S Hothi
- Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK.
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Hothi SS, Booth SW, Sabir IN, Killeen MJ, Simpson F, Zhang Y, Grace AA, Huang CLH. Arrhythmogenic substrate and its modification by nicorandil in a murine model of long QT type 3 syndrome. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2008; 98:267-80. [DOI: 10.1016/j.pbiomolbio.2009.01.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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